Trident is the name of the layout engine for the Microsoft Windows version of Internet Explorer. It was first introduced with the release of Internet Explorer version 4 in October 1997, has been steadily upgraded and remains in use today.

Trident was designed as a software component to allow software developers to easily add web browsing functionality to their own applications. It presents a COM interface for accessing and editing web pages in any COM supported environment, like C++ and .NET. For instance, a web browser control can be added to a C++ program and Trident can then be used to access the page currently displayed in the web browser and retrieve element values. Events from the web browser control can also be captured. Trident functionality becomes available by connecting the file mshtml.dll to the software project.

Versions

• Trident (IE4)
• Trident II (IE5) (improved CSS1.0 support and had sweeping changes in CSS2 rendering)
• Trident III (IE5.5) (corrected issues with CSS handling)
• Trident IV (IE6) (corrected the box-model and added "Quirks Mode" with DTD switching)

Trident-based applications

• Internet Explorer 4.0 and onwards.
• Windows Explorer in all versions of Windows from Windows 98 onwards.
• And various Internet Explorer shells
• Microsoft's Outlook and Outlook Express use Trident to render HTML Messages and the "Outlook Today" screen
• Microsoft's Encarta and related products
• Microsoft's Windows Media Player uses Trident to render media lists
• Valve's Steam software uses Trident to render the "Browse Games" and "Update News" sections

See also

• List of layout engines
• Comparison of layout engines